Risks

Mammograms expose you to low-dose radiation. The dose is very low, though, and for most women the benefits of regular mammograms outweigh the risks posed by this amount of radiation.

Mammograms aren't always accurate. The accuracy of the procedure depends in part on the technique used and the experience and skill of the radiologist. Other factors — such as your age and breast density — may result in false-negative or false-positive mammograms.

Mammograms in younger women can be difficult to interpret. The breasts of younger women contain more glands and ligaments than do those of older women, resulting in dense breast tissue that can obscure signs of cancer. With age, breast tissue becomes fattier and has fewer glands, making it easier to interpret and detect changes on mammograms.

Having a mammogram may lead to additional testing. Among women of all ages, about 10 percent of mammograms require additional testing, including additional imaging tests such as ultrasound, and a procedure (biopsy) to remove a sample of breast tissue for laboratory testing. However, most abnormal findings detected on mammograms aren't cancer.

If you're told that your mammogram is abnormal, your radiologist will want to compare it with previous mammograms. If you have had mammograms performed elsewhere, your radiologist will ask for your permission to have them sent to the radiology center so that they can be compared with the current mammogram.

Screening mammography can't detect all cancers. Some cancers detected by physical examination may not be seen on the mammogram. A cancer may be too small or may be in an area that is difficult to view by mammography, such as your armpit. Mammograms can miss 1 in 5 cancers in women.

Not all of the tumors found by mammography can be cured. Certain types of cancers are aggressive, grow rapidly and spread early to other parts of your body.

Smith RA, et al. Cancer screening in the United States, 2016: A review of current American Cancer Society guidelines and current issues in cancer screening. CA: A Cancer Journal for Clinicians. 2016;66:95.

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